Mechanical pencil



. c. R. KEERAN MECHANICAL PENCIL Filed Feb.A 14, 1931 Oct. 24, 1933.

Patented Oct.i24, 1933 UNTED STATES PATENT OFFICE 1,932,371 MECHANICALPENCIL Ware Appiication February 14, 1931.' serial No'. 515,684

11 Claims.

This invention relates to mechanical pencils of the type in whichthelead is both propelled and withdrawn positively by operation of themechanism, and which includes a magazine for spare leads and a holder inwhich an eraser is removably carried. The invention consists in certainimprovements in the mechanism and in the means for mounting it in thebarrel of the pencil designed to facilitate assembly and disassembly, sothat minor repairs can be readily made by the user or by the dealerwithout the necessity of shipping the device back to the factory. Theinvention therefore comprises certain features and elements ofconstruction herein shown and described, as indicated by the appendedclaims.

In the` drawing:

Figure 1 is an axial section on a scale somewhat larger than the actualsize of the article, and showing the pencil equipped with a mechanismembodying this invention.

Figure 2 is an axial section on a still larger scale, showing the lowerend portion of the pencil and the lead-propelling mechanism therein.

Figure 3 is a sectional View similar to Figurer 2, showing thepropelling mechanism in position after ejecting a lead.

Figure v4 is a transverse section taken as indicated at vline 4-4 onFigure 2.

Figure 5 is a side elevation Apartly in section of the guide tube forthe lead-propelling plunger with the spare lead chamber and erasersocket which are associated therewith.

l Figure 6 is a detail view of the lead-propelling carrier and plunger.f

l While the mechanism herein illustrated and its manner of operation arefamiliar in a general way, the particular arrangement of theY parts andtheir assembly in the pencil barrel has been worked out to insuresatisfactory operation, but particularly to simplify repairs oradjustments which may occasionally be required and to provide for takingupwear in the working parts'. As illustrated, the pencil barrel, 1 isformed with a bore at 2, in which the spirally slotted tube, 3, isaccommodated. The lower end of this tube, 3, is tightly secured in a"sleeve, 4, which itself is forced into an enlarged bore, 5, of thebarrel adjoining the bore, 2, This anchors the spiral tube, 3, in thebarrel as a permanent fixture therein. Journaled Within the tube, 3, forrotation about its axis is the slotted tube, 6, which is permanentlyanchored in the lower end of a cylindrical chamber, '7, serving as aspare lead magazine, as indicated in Figure 1, and the upper end of saidchamber, 7, is surmounted by an enlarged cylindrical (Cl. 1Z0-18)portion, 8, which functions as a socket to receive the metallic holder,9, in which'the removable eraser, l0, is carried. The cylindrical parts,7 and 8, may be made integral by a familiar drawing process, such as isemployed in the manufacture of cartridge shells, and the slotted tube,6, may be attached to the part, '7, in any suitable manner,

as by flaring and swedging over its extreme end in the form of a flange,6a, opposing the slight shoulder, 6b, which abuts the outer or lowerside 65 of the bottom wall of the cylinder, 7 Since the tube, 6, ishollow, a disk, 1l, will be inserted to form a closed bottom Wall forthe magazine chamber, 7.

At the opposite or lower end the slotted tube, 6, is threaded to receivea retaining nut, 12. The iixed sleeve, 4, provides at its outer end ashoulder, 14, which serves as a stop for the nut, 12, and preferably awasher, 13, is interposed between the nut and said shoulder tofacilitate rotation of the tube, 6. At'the upperr end of the barrel ametallic bushing, 15, is inserted yinto a counterbore, 16, with itsiiange, 15a, engaging the upper end of the barrel, l. This bushingserves as a journal bearing for the tubular part, 7, while its flange,15a, 80 provides a stop shoulder for engaging the transversev wall, 8a,oi the eraser socket, 8. Thus, by proper adjustment of the nut, 12, therotative member, consisting of parts, 6, 7 and 8, maybe secured in thebarrel, 1, with the stop shoulders accurately related to permit relativerotation oi the parts without appreciable end play. Preferably, the nut,12, and the end of the tube, 6, are formed with a tapered threadsomewhat similar to a pipe thread, so that the nut will hold tightlywithout any tendency to back olf, but may be threaded somewhat fartheronto the sleeve, 6, for taking up wear if required.

The'lead, indicated at 17, is held in a familiar manner by thefrictional grip of a hollow plunger, 18, whose end is slightly flared at18a by reaming to facilitate insertion of the blunt end of the leadtherein. At its opposite end the plunger, 18, is formed with a laterallyprojecting lug, 19, which extends through the slot, 20, of the tube, 6,and into the spiral slot, 21, of the tube, 3. Thus, when the tube, 6, isrotated, the lug, 19, is forced to traverse the spiral slot, 21, causingthe plunger, 18, to slide longitudinally within the tube,

6, and move the lead through the tip, 22. The frictional grip of thehollow plunger, 18, upon the end of the lead, 1'7, permits the plungerto withdraw the lead within the barrel as well as to propel it outwardlythrough the tip, 22, depending on the direction of rotation of the tube,6.

However, the propulsion of the lead outwardly is assisted by thepresence of a solid plunger, 23, within the hollow plunger, 18, andprovided with a lug, 24, which. also engages the spiral slot, 21, of thetube, 3. The lugs, 19 and 2li, are longitudinally spaced apart, and asshown, this spacing is such that they engage consecutive turns of theslot, 2l. When the lead is so nearly used up that only a short pieceremains in the tip, 22, and plunger, 18, the plunger will have traveledits full range into the bore, 25, adjacent the shoulder, 26, of the tip,22, and at this position the lug, 19, will be rested against the innei`shoulder, de, of the sleeve, e. Further rotation oi the sleeve, 6, ispermitted by the terminal portion, 21a, of the slot, 21, which is formedat right angles to the axis instead o obliquely, like the helicalportion, and while the lug, 19, is swinging through a partial turnthrough this terminal portieri, 21a, the lug, 24, continues to traversethe adjacent spiral portion, thus moving the plunger, 23, downwardlywithin the hollow plunger, 18, and ejecting the fragment or lead, 17a,therefrom, as indicated in Figure 3.

As shown in Figure 1, the pencil may be provided with a pocket clip, 30,which is in general of the usual design, having a ball end, 3l, formedon its spring tang which extends along the barrel,

, l, near its Lipper end. The tang is oiset at 32 to pass through anaperture, preferably in the form of a slot, 1a, in the barrel, andwithin the barrel a terminal portion, 33, extends against the wall ofthe counterbore, 16. For locking the clip in this position the bushing,15, is reduced at its inner end at 15b, forming an annular groove inwhich the eXtreme end of the terminal, 33, is engaged. This groovehaving a depth substantially equal to the thickness of the stock at 33,holds g the clip firmly, because its transverse portion, 32,

drawing the bushing, 15, so as to release the part, 33.

In fact, the removal of any part of the mechanism except the spirallyslotted tube, 3, is readily accomplishedby unscrewing the nut, 12, whichreleases the rotative element comprising the tubular parts, 6, 'l and B.Since the slot, 20, extends through the threaded end of the tube, 6,this rotative element may be withdrawn upwardly 'through the barrel assoon as the nut, 12, and washer, 13, Vare taken ofi. If these parts arerst turned counter-clock-wise far enough to feed the plungers, 18 and23, to the upper end of the spiral tube, 3, the latter will drop out ofthe barrel readily, or may even remain frictionally engaged with thetube, 6; otherwise, the removal of the tube, 6, will permit the plungerlugs, 19 and 2li, to be disengaged from the slot, 21, by reason of theextra clearance afforded in the tube, 3, and these small parts can beeasily shaken out of the barrel. l

The tip, 22, is shown screwed onto the threaded end oi the sleeve orbushing, 4., at 22a, and thus forms a removable housing for the nut, l2,serving to prevent any disturbance rofthe adjustment of the nut when theparts are assembled. It is well understood that when the barrel, 1, ismade of ceiluloid or like material it is sometimes subject to a gradualshrinkage, ltending to shorten its length; in this event the` threadedengagement of the tip, 22a, will .permit it always to be screwed tightlyagainst the lower end of the barshr -i away from the ages.

vI claim:

1. 1n a pencil comprising a tubular barrel and a tip thereon, alead-propelling mechanism, means located near the tip securing saidmechanism within the barrel and -nea-ns securing the tip to the barrelindependent oithe means securing the propelling mechan sm.

2. in a pencil comprising a tubular barrel and `a lead-operatingmechanism functioning therein,

means for loclting said mechanism in said barrel, a tip detachablysecured to the barrel independently of said mechanism locking means,said locking means being accessible upon detachment of the tip andoperable at will for release removal of the lead-operating mechanism.

3. In a mechanical pencil comprising a tubular barrel and alead-operating mechanismv functioning therein, a removable tip for thewriting end ci the pencil and a nut housed in said tip securing saidmechanism in said barrel.

4. In a mechanical pencil comprising a barrel and a lead-feedingmechanism functioning therein, and means for locking said mechanism inoperative position in said barrel, said locking means having a bore topermit the lead to be fed therethrough.

5. in a mechanical pencil comprising a tubular barrel, a lead-operatingmechanism functioning therein, a tubular lead magazine forming the upperpart of said operating mechanism, said magazine being enlarged at itsouter end to form a head for the pencil and serve as an eraser seat orsocket, said magazine and head being formed of a single piece of tubingbut or" diierent diameters respectively. y

roo

6. In a mechanical pencil comprising a tubular barrel and a lead-feedingmechanism therein,` a

bushing inserted inthe writing end of the barrel, having means forarresting the feeding movement of the mechanism, and means for attachinga tip member to said bushing.

7. 1n a mechanicalpencil comprisinga tubular 1 barrel and a lead-feedingmechanism therein, a bushing secured in the writing end of said barrelhaving an internal shoulder which serves as a stop for the lead-feedingmovement of the mechf anism, the bushing itself providing abearing forcentering the rotating part of the nieclflanisrnl in the barrel, andsaid bushing including an eXtension beyond thev barrel formed to receivea detachable tip for the pencil.

8. In a mechanical pencil comprising a tubular barrel, a lead-feedingmechanism including a longitudinally slotted tube, a lead vholder yand aleadY expeller functioning therein, a bushing fixed in the writing endof the barrel, said mechanism;` also including a shoulderedpart stoppedagainst bushing disposed at the writing end and the lead tube extendingthrough said bushing, together with a washer on the tube between thebushing and the nut, and means on the mechanism engaging the barrel tocheck the mechanism and said lead tube against movement toward thewriting end of the pencil while permitting rotation of the mechanismabout its axis in the barrel.

10. In a mechanical pencil comprising a barrel with a lead-operatingmechanism therein which includes a lead tube extending beyond one end ofthe barrel, and a head protruding from the op-V the barrel at its upperend, a threaded -bushing tted tightly in the bore of the barrel at thelower end with its threaded portion protruding therefrom, alead-operating mechanism extending throughout the barrel and providedwith a head having a transverse shoulder abutting the flange of thebushing at the upper end, said mechanism including a part whichprotrudes from the bushing at the lower end of the barrel, saidprotruding part being threaded, and a stop nut adjustably screwedthereon, together with a hollow tip forming an extension of the barreland threaded for securement on the threaded protruding portion of thebushing at the lower end of said barrel, whereby said tip is removableto afford access to the nut for dismantling the mechanism or adjustingit to take up wear or compensate for shrinkage of the barrel.

CHARLES R. KEERAN.

